1. Field of the Invention
The present invention relates to a valve apparatus.
2. Description of Related Art
Conventionally, an air intake apparatus has been known as the above valve apparatus, and the air intake apparatus includes an intake manifold, a valve element, a valve shaft, a bearing housing, and an actuator, for example. The intake manifold serves as a body, and the valve element is provided inside the intake manifold to open and close a predetermined flow path. The valve shaft rotates the valve element, and the bearing housing rotatably support the valve shaft. The actuator applies a driving force to the valve shaft.
In a conventional valve apparatus 100 as the air intake apparatus, as shown in FIG. 4, fixing means 101, such as a bolt, fixes a bearing housing 103 on an outer surface of a body 102, and further, similar fixing means 104 fixes an actuator 105 to the bearing housing 103. It should be noted that the predetermined flow path, which is opened and closed by a valve element, is a flow path that generates a vortex flow in intake air based on the operation for reducing the opening of the flow path, for example.
It is required that the bearing housing 103 be not easily detached or removed from the body 102 in order to limit misalignment of the valve shaft. According to the above conventional valve apparatus 100, in order to prevent the easy-detachment of the bearing housing 103, the fixing means 101 may be covered by a potting material, and also the fixing means 101 may be provided with a tamper-proof threaded member.
However, both of (a) the covering of the fixing means 101 by using the potting material and (b) the use of the tamper-proof threaded member may lead to an increase in cost. Thus, due to the need for reduction in cost, there is needed another technique for limiting the detachment of the bearing housing 103. Also, the bearing housing 103 may be needlessly detached in a case, where the actuator 105 is detached for repair. Thus, there should be a countermeasure for limiting the needless detachment.
It should be noted that JP-A-2004-124933 corresponding to GB2393218 discloses an air intake apparatus, which includes a protection member and an actuator. The protection member is disclosed as a guide member 70, and is named as a bearing housing hereinafter. The bearing housing functions as the valve shaft and also covers a bearing from outside thereof to protect the bearing. The actuator covers the bearing housing from outside thereof. According to the air intake apparatus, the bearing housing is rigidly fixed and provided in a state, where the bearing housing is provided between the intake manifold and the actuator, and where the actuator is secured to the intake manifold by a screw. Thus, when the screw is removed in order to detach the actuator, the bearing housing is also released from the rigid state, where the bearing housing is rigidly fixed, thereby the valve shaft may be misaligned disadvantageously.